Diabetic Skin Wounds Research Articles

Schlafen5, regulated by the AP-1 family transcription factor c-Fos, affects diabetic wound healing through modulating PI3K/Akt/NRF2 axis

Diabetic ulcers (DUs) present significant physical and psychological challenges to patients, while placing a significant economic burden on healthcare systems. Promoting the blood vessel regeneration is critical for ensuring the delivery of essential nutrients and oxygen to the injured area, thereby supporting the healing process. To gain insight into the complex molecular mechanisms that drive DUs healing, we performed a comprehensive analysis of single-cell transcriptomic data from healing and non-healing DU states. This analysis revealed a key role of Schlafen5 (SLFN5) signal in modulating key healing processes. SLFN5, a protein known to regulate cellular processes like migration, invasion, inflammation, and cell death, emerged as an important player. Yet, although it is prominent, the specific function of SLFN5 in diabetic skin wounds remained unclear. Our study discovered a marked elevation of SLFN5 levels in endothelial cells within DUs and its suppression notably mitigates the oxidative stress and endoplasmic reticulum stress (ERS)-mediated cell death pathways, including pyroptosis and apoptosis. This finding implies that excessive SLFN5 activity might obstruct wound closure by intensifying cellular stress reactions. Upon further investigation, we found that the antioxidant and cytoprotective effects were mediated through enhanced NRF2 activity, facilitated by the PI3K/Akt signaling pathway. Moreover, our investigation identified that c-Fos as a pivotal transcription factor governing SLFN5 transcription during the development of DUs, offering valuable insights into the regulation of SLFN5 expression. In diabetic mice model, SLFN5 knockdown accelerating wound healing, which was intervened by PI3K/Akt inhibitor. These results hold significant therapeutic potential, indicating that targeting SLFN5 may represent a novel and effective strategy for improving wound healing outcomes in patients with DUs.

Diabetic rats skin wounds treated with heterologous fibrin sealant followed by photobiomodulation therapy.

Diabetes mellitus is characterized by elevated blood glucose levels causing sometimes impairment of the body's ability to repair itself. Promising treatments for tissue repair have included photobiomodulation therapy and heterologous fibrin biopolymer (HFB). This study aimed to evaluate the impact of photobiomodulation therapy by LED, both as a standalone treatment and in conjunction with heterologous fibrin biopolymer in treatment of skin lesions of diabetic rats. Diabetes was induced using alloxan. Full-thickness skin wounds were induced on the backs of 56 Wistar rats, which were randomly allocated into four groups: control group, heterologous fibrin biopolymer group, photobiomodulation therapy by LED group, and photobiomodulation therapy by LED combined with heterologous fibrin biopolymer group. The treatments spanned two experimental periods, lasting 7 and 14 days. Notably, the HFB group exhibited results similar to those of the LED group concerning wound regression, while demonstrating superior resistance to healing. Interestingly, the LED + HFB group showed greater skin damage at 7 days, but an improved repair process at 14 days compared to the control group. The findings indicate that combining photobiomodulation by LED with HFB did not enhance wound healing in diabetic rats beyond the effects of each treatment alone. Both treatments were effective individually, with HFB showing particular strength in promoting collagen maturation and improving tissue biomechanical properties.This study contributes tothe ongoing body of research on skin repair with this innovative HFB. Future clinical trials will be essential to validate this proposition.

Improving diabetic wound healing: The therapeutic potential of allulose supplement in diabetic skin tissue repair and inflammation modulation

The increasing prevalence of type 2 diabetes mellitus (T2DM) worldwide presents significant challenges in the management of impaired tissue repair in diabetic skin wounds, which has emerged as a critical health concern. Addressing this issue while minimizing adverse effects remains crucial. Allulose has been shown to exhibit hypolipidemic and anti-inflammatory properties, alleviating obesity and atherosclerosis by improving insulin resistance and impaired glucose tolerance. However, its underlying effects and mechanisms in repairing diabetic skin damage remain poorly understood. In this study, we demonstrated that oral administration of allulose remarkably ameliorated T2DM-compromised skin tissue wound associated with the stimulation of skin granulation, surrounding tissue formation, and activated fibroblasts, under high-fat diet (HFD) feeding condition. In addition, administration partially promoted collagen deposition, reduced M1 macrophage polarization, facilitated neovascularization, and mitigated tissue inflammation in the T2DM rats upon HFD feeding. Moreover, allulose could significantly alleviate high glucose stress condition-induced inflammatory response, correlative with modulation of p38/NLRP3/Caspase-1 signaling. In addition, allulose could also ameliorate high glucose stress-compromised cell viability and proliferative capacity, related to stimulation of mTOR pathway in part. Taken together, our study revealed that T2DM compromised some certain factors which are crucial for skin tissue healing and wound repair upon HFD condition. The work highlighted the potential beneficial effects of orally administered allulose for healing diabetic skin wounds and supported a novel strategy for managing diabetes patients adjunctively with allulose dietary supplement.

The Quantitative InVivo Assessment of Diabetic andNon-Diabetic Skin Wound Healing Using Phasor-FLIM Approach.

A quantitative assessment of wound status in a murine model was developed using phasor plot presentation of fluorescence lifetime imaging microscopy (FLIM) data. The quantitative assessment is based on calculating Bhattacharyya distance between g coordinates of FLIM data phasor plot density distributions of wound and healthy skin. The approach was validated for both diabetic and non-diabetic mice wounds, including during low-dose photodynamic therapy (LDPDT). Analysis revealed a shift in the FLIM data phasor plot g coordinates, suggesting altered metabolic processes involved in wound healing. Bhattacharyya distances in the LDPDT groups were closer to zero compared to the control group, which was not treated by LDPDT. Bhattacharyya distances in the non-diabetic LDPDT groups were closer to zero compared to the diabetic LDPDT groups that is consistent with the literature regarding the positive role of LDPDT in accelerating wound healing and the role of diabetes mellitus in impairing wound healing.

Efficacy and mechanism of Schisandra chinensis active component Gomisin A on diabetic skin wound healing: network pharmacology and in vivo experimental validation

Ethnopharmacological relevanceSchisandra chinensis (Turcz.) Baill., a common traditional Chinese herbal medicine, has been used for the treatment of diabetes mellitus and its complications. However, the major active component for treating diabetic foot ulcers, a serious complication of diabetes mellitus, was unclear. This study aimed to predict the treatment effect of the active components in Schisandra chinensis against diabetic skin wound using network pharmacology and to confirm the underlying mechanism using a diabetic skin wound model in vivo. Aim of the studyTo study the effects and underlying mechanisms of Schisandra chinensis and its main component Gomisin A on diabetic skin wound healing by network pharmacology and high-fat diet (HFD)-induced obese mice model in vivo. Materials and methodsTo determine the effectiveness of Schisandra chinensis on diabetic skin wound, network pharmacology was first used. Components of Schisandra chinensis were obtained from the Traditional Chinese Medicine Systems Pharmacology database. The active components were further verified through absorption, distribution, metabolism and excretion. The potential targets of the active components were identified from the Traditional Chinese Medicine Systems Pharmacology, SwissTargetPrediction, TargetNet, and the Comparative Toxicogenomics Database. Targets related to diabetic skin wound were collected from the GeneCards, OMIM, DisGeNET, and PharmGKB databases. The interaction network formed by the intersection of the two datasets was analyzed using Gephi. Network-based proximity was used to predict the network distance between the active components of Schisandra chinensis and diabetic skin wound. Gomisin A was found to have the lowest Z-score and was administered either orally or via topical injection to HFD-induced obese mice daily until the wounds healed, and its effects on skin wound healing were evaluated. ResultsOnly five active ingredients of Schisandra chinensis were screened in our system: Gomisin A, Longikaurin A, Deoxyharringtonine, Wuweizisu C, and Interiotherin B, which can regulate biological processes related to diabetic skin wound, including positive regulation of phosphorous metabolic process, positive regulation of cell migration, and response to wounding. Network proximity analysis found that Gomisin A has the closest distance-based Z-score among the diabetic skin wound modules and drug targets in the human protein-protein interaction network. The HFD-induced obese mice model further revealed that Gomisin A accelerated skin wound healing by increasing insulin sensitivity and decreasing the advanced glycation end-products mediated toll-like receptor 4 (TLR4)-p38 MAPK-IL6 inflammation signaling pathway. ConclusionsThe network pharmacology and in vivo studies indicated that Gomisin A from Schisandra chinensis played a crucial role in improving diabetic skin wound healing.

Enhancing diabetic foot ulcer healing: Impact of the regulation of the FUS and ILF2 RNA‑binding proteins through negative pressure wound therapy.

Diabetic foot ulcer (DFU) is a destructive complication of diabetes. Negative pressure wound therapy (NPWT) promotes DFU wound healing through an undetermined mechanism. In the present study, RNA sequencing was performed on wound granulation tissue from 3 patients with DFU before and after 1 week of NPWT. The fused in sarcoma (FUS) and interleukin enhancer binding factor 2 (ILF2) encoding RNA‑binding proteins (RBPs) were screened from the sequencing data, and wound tissue samples from 24 patients with DFU were validated and analyzed before and after receiving NPWT by reverse transcription‑quantitative PCR, western blotting and immunohistochemistry. In addition, in vitro and in vivo experiments were conducted to determine the effect of the expression of FUS and ILF2 on the function of human epidermal keratinocyte cells (HaCaT cells) and the healing of diabetic skin wounds. The results indicated that NPWT induced the upregulation of 101 genes and the downregulation of 98 genes in DFU wound granulation tissue. After NPWT, the expression of FUS and ILF2 was significantly upregulated (P<0.05). Pearson's correlation coefficient showed that the changes in FUS and ILF2 before and after NPWT were negatively correlated with changes in white blood cells, the neutrophil percentage, C‑reactive protein, tumor necrosis factor‑α, reactive oxygen species, lipid peroxides, matrix metalloproteinase (MMP) 2 and MMP9 (P<0.05), but positively correlated with the anti‑inflammatory factor, IL‑4 (P<0.01). There was also a positive correlation (P<0.05) with the 4‑week ulcer healing rate. Additionally, the knockdown of FUS and ILF2 expression inhibited the proliferation and migration of HaCaT cells, while increasing cell apoptosis. In vivo, the knockdown of FUS and ILF2 significantly reduced the rate of skin wound healing in diabetic mice. The results of the present study therefore provide new insights into the mechanism by which NPWT promotes DFU wound healing. In conclusion, the RBPs, FUS and ILF2, promoted DFU wound healing by regulating the function of keratinocytes and reducing the inflammatory response and oxidative stress.

Bioinspired Collagen Scaffold Loaded with bFGF-Overexpressing Human Mesenchymal Stromal Cells Accelerating Diabetic Skin Wound Healing via HIF-1 Signal Pathway Regulated Neovascularization.

The healing of severe chronic skin wounds in chronic diabetic patients is still a huge clinical challenge due to complex regeneration processes and control signals. Therefore, a single approach is difficult in obtaining satisfactory therapeutic efficacy for severe diabetic skin wounds. In this study, we adopted a composite strategy for diabetic skin wound healing. First, we fabricated a collagen-based biomimetic skin scaffold. The human basic fibroblast growth factor (bFGF) gene was electrically transduced into human umbilical cord mesenchymal stromal cells (UC-MSCs), and the stable bFGF-overexpressing UC-MSCs (bFGF-MSCs) clones were screened out. Then, an inspired collagen scaffold loaded with bFGF-MSCs was applied to treat full-thickness skin incision wounds in a streptozotocin-induced diabetic rat model. The mechanism of skin damage repair in diabetes mellitus was investigated using RNA-Seq and Western blot assays. The bioinspired collagen scaffold demonstrated good biocompatibility for skin-regeneration-associated cells such as human fibroblast (HFs) and endothelial cells (ECs). The bioinspired collagen scaffold loaded with bFGF-MSCs accelerated the diabetic full-thickness incision wound healing including cell proliferation enhancement, collagen deposition, and re-epithelialization, compared with other treatments. We also showed that the inspired skin scaffold could enhance the in vitro tube formation of ECs and the early angiogenesis process of the wound tissue in vivo. Further findings revealed enhanced angiogenic potential in ECs stimulated by bFGF-MSCs, evidenced by increased AKT phosphorylation and elevated HIF-1α and HIF-1β levels, indicating the activation of HIF-1 pathways in diabetic wound healing. Based on the superior biocompatibility and bioactivity, the novel bioinspired skin healing materials composed of the collagen scaffold and bFGF-MSCs will be promising for healing diabetic skin wounds and even other refractory tissue regenerations. The bioinspired collagen scaffold loaded with bFGF-MSCs could accelerate diabetic wound healing via neovascularization by activating HIF-1 pathways.

In Situ Triggered Self-Contraction Bioactive Microgel Assembly Accelerates Diabetic Skin Wound Healing by Activating Mechanotransduction and Biochemical Pathway.

Chronic nonhealing skin wounds, characterized by reduced tissue contractility and inhibited wound cell survival under hyperglycemia and hypoxia, present a significant challenge in diabetic care. Here, an advanced self-contraction bioactive core-shell microgel assembly with robust tissue-adhesion (SMART-EXO) is introduced to expedite diabetic wound healing. The SMART-EXO dressing exhibits strong, reversible adhesion to damaged tissue due to abundant hydrogen and dynamic coordination bonds. Additionally, the core-shell microgel components and dynamic coordination bonds provide moderate rigidity, customizable self-contraction, and an interlinked porous architecture. The triggered in situ self-contraction of the SMART-EXO dressing enables active, tunable wound contraction, activating mechanotransduction in the skin and promoting the optimal fibroblast-to-myofibroblast conversion, collagen synthesis, and angiogenesis. Concurrently, the triggered contraction of SMART-EXO facilitates efficient loading and on-demand release of bioactive exosomes, contributing to re-epithelialization and wound microenvironment regulation in diabetic mice. RNA-seq results reveal the activation of critical signaling pathways associated with mechanosensing and exosome regulation, highlighting the combined biomechanical and biochemical mechanisms. These findings underscore SMART-EXO as a versatile, adaptable solution to the complex challenges of diabetic wound care.

TWEAK increases angiogenesis to promote diabetic skin wound healing by regulating Fn14/EGFR signaling.

Tumor necrosis factor-like weak inducer of apoptosis (TWEAK), a member of tumor necrosis factor superfamily, can bind to fibroblast growth factor-inducible 14 (Fn14) receptor and stimulate angiogenesis. The interaction between epidermal growth factor receptor (EGFR) and endothelial growth factor (EGF) leads to EGFR signal transduction and promotes angiogenesis. The objective of this study was to explore whether TWEAK participated in the diabetic skin wound healing by regulating Fn14/EGFR signaling. Human umbilical vein endothelial cells (HUVECs) were treated with 35 mmol/L d-glucose and classified into the Control Group, High Glucose (HG) Group and HG + TWEAK Group. Then, the TWEAK expression and the proliferation, migration and tubule formation of HUVECs were detected, respectively. Invivo experiment, the diabetic model was established by injecting streptozotocin (STZ, 50 mg/kg) into male BALB/c mice. On the back of successfully modeled diabetic mice, a full-thickness skin wound of 6 mm diameter was formed. Then, the mice were randomly assigned into three groups: Blank Group, Phosphate Buffer Saline (PBS) Group, and TWEAK Group. Subsequently, expression levels of TWEAK, Fn14, EGFR and vascular endothelial growth factor (VEGF)-A were measured, and the CD31 expression in the wounded skin tissue of mice was checked by immunohistochemistry staining. The expression level of TWEAK in HUVECs of HG Group decreased significantly, as well as the viability, migration, and tubule formation of cells. After over-expression of TWEAK, the cell viability, migration, and tubule formation abilities of HUVECs recovered remarkably. Invivo, the wound healing rate of diabetic mice was raised, the neovascularization was increased, and the CD31 expression in the wounded tissue was obviously upregulated after injection with recombinant TWEAK antibody. TWEAK stimulates angiogenesis and accelerates the wound healing of diabetic skin by regulating Fn14/EGFR signaling.

Salvianolic acid B improves diabetic skin wound repair through Pink1/Parkin-mediated mitophagy

Diabetic skin wound is a disturbing and rapidly evolving clinical issue. Here, we investigated how salvianolic acid B (Sal B) affected the diabetic wound healing process. Following Sal B administration, histopathological damage was investigated by H&E and Masson staining, and CD34, apoptosis and mitophagy markers were measured by immunofluorescence, immunohistochemistry, and western blotting. Migration, proliferation, and mitochondrial function of high glucose (HG) –induced HMEC-1 cells were measured. The effects of si-Parkin on endothelial cell migration, apoptosis and mitochondrial autophagy were examined. Sal B alleviated inflammatory cell infiltration and promoted angiogenesis in skin wound tissue. Apoptosis and mitophagy were ameliorated by Sal B in diabetic skin wound tissues and HG-induced HMEC-1 cells. Parkin inhibition impaired the migratorypromoted cell apoptosis and inhibited mitophagy of HMEC-1 cells. This finding demonstrated that Sal B promoted diabetic skin wound repair via Pink1/Parkin-mediated mitophagy, improved our understanding of the diabetic wound healing process.

Rapid and Controllable Multilayer Cell Sheet Assembly via Biodegradable Nanochannel Membranes

AbstractThe ability to precisely arrange and control the assembly of diverse cell types into intricate 3D structures remains a critical challenge in tissue engineering. Herein, a versatile and programmable 3D cell sheet assembly is described technology by developing a biodegradable nanochannel (BNC) membrane to fulfill this unmet need. This membrane, hierarchically assembled from 2D nanomaterial aggregates, exhibits both exceptional fluid permeability and rapid biodegradation under physiological conditions. The unique properties of the BNC membrane enable precise spatial and temporal control over cell assembly, facilitating the creation of complex 3D cellular architectures. The BNC membrane is integrated with a programmable negative‐pressure‐based cell assembly strategy to form single and multicellular 3D sheets in a highly controllable manner. To demonstrate the feasibility and translatability of this technology in the field of tissue engineering approaches to screen stem cell‐derived therapeutics with “core–shell” macrophage‐fibroblast multicellular patterns and treat murine diabetic skin wounds via scaffold‐free 3D adipose‐derived mesenchymal stem cell (ADMSC) sheets are devised. In summary, the results demonstrate that the BNC membrane‐based 3D cell sheet assembly approach significantly advances current tissue engineering capabilities, offering substantial potential for both regenerative medicine applications and the development of physiologically relevant disease models.

Electrical Stimulating Redox Membrane Incorporated with PVA/Gelatin Nanofiber for Diabetic Wound Healing.

Chronic wounds adversely affect the quality of life. Although electrical stimulation has been utilized to treat chronic wounds, there are still limitations to practicing it due to the complicated power system. Herein, an electrostimulating membrane incorporated with electrospun nanofiber (M-sheet) to treat diabetic wounds is developed. Through the screen printing method, the various alternate patterns of both Zn and AgCl on a polyurethane substrate, generating redox-mediated electrical fields are introduced. The antibacterial ability of the patterned membrane against both E. coli and S. aureus is confirmed. Furthermore, the poly(vinyl alcohol) (PVA)/gelatin electrospun fiber is incorporated into the patterned membrane to enhance biocompatibility and maintain the wet condition in the wound environment. The M-sheet can improve cell proliferation and migration in vitro and has an immune regulatory effect by inducing the polarization of macrophage to the M2 phenotype. Finally, when applied to a diabetic skin wound model, the M-sheet displays an accelerated wound healing rate and enhances re-epithelialization, collagen synthesis, and angiogenesis. It suggests that the M-sheet is a simple and portable system for the spontaneous generation of electrical stimulation and has great potential to be used in the practical wound and other tissue engineering applications.

Polydopamine-armored zeolitic imidazolate framework-8-incorporated zwitterionic hydrogel with multifunctional properties for infected wound healing

Diabetic skin wound healing is compromised by bacterial infections, oxidative stress, and vascular disruption, leading to delayed recovery and potential complications. This study developed an antibacterial, antioxidant, and adhesive hydrogel dressing that promotes rapid bacterial-infected diabetic wound healing using the biological macromolecule of polydopamine (PDA). This hydrogel comprised PDA-armored zeolitic imidazolate framework-8 nanoparticles (PDA@ZIF-8 NPs) combined with a second armor of zwitterionic polymer network (poly(acrylamide-co-sulfobetaine methacrylate); PAS), realizing low concentration Zn2+ release, good adhesion (14.7 kPa for porcine skin), and improved tensile strength (83.2 kPa). The hydrogel exhibited good antibacterial efficacy against both Staphylococcus aureus (S. aureus, 92.8 %), Escherichia coli (E. coli, 99.6 %) and methicillin-resistant S. aureus (MRSA, 99.2 %), which was attributed to the properties of the incorporated PDA@ZIF-8 NPs. Notably, in vitro, the PDA@ZIF-8 PAS hydrogel not only promoted fibroblast proliferation and migration but also facilitated endothelial cell angiogenesis. In vivo, the PDA@ZIF-8 PAS hydrogel retained its Zn2+-releasing function and effectively suppressed bacterial growth in infected wounds, thereby accelerating the regeneration of both normal and diabetic wounds. This multiarmored hydrogel is a promising sustained-release carrier for functional metal ions and drugs, making it applicable for not only skin healing, but potentially the regeneration of other complex tissues.

Deep Red Light Driven Hydrogen Evolution by Heterojunction Polymer Dots for Diabetic Wound Healing

AbstractWe describe small heterojunction polymer dots (Pdots) with deep‐red light catalyzed H2generation for diabetic skin wound healing. The Pdots with donor/acceptor heterojunctions showed remarkably enhanced photocatalytic activity as compared to the donor or acceptor nanoparticles alone. We encapsulate the Pdots and ascorbic acid into liposomes to form Lipo‐Pdots nanoreactors, which selectively scavenge ⋅OH radicals in live cells and tissues under 650 nm light illumination. The antioxidant capacity of the heterojunction Pdots is ~10 times higher than that of the single‐component Pdots described previously. Under a total light dose of 360 J/cm2, the Lipo‐Pdots nanoreactors effectively scavenged ⋅OH radicals and suppressed the expression of pro‐inflammatory cytokines in skin tissues, thereby accelerating the healing of skin wounds in diabetic mice. This study provides a feasible solution for safe and effective treatment of diabetic foot ulcers.

Deep Red Light Driven Hydrogen Evolution by Heterojunction Polymer Dots for Diabetic Wound Healing.

We describe small heterojunction polymer dots (Pdots) with deep-red light catalyzed H2 generation for diabetic skin wound healing. The Pdots with donor/acceptor heterojunctions showed remarkably enhanced photocatalytic activity as compared to the donor or acceptor nanoparticles alone. We encapsulate the Pdots and ascorbic acid into liposomes to form Lipo-Pdots nanoreactors, which selectively scavenge ⋅OH radicals in live cells and tissues under 650 nm light illumination. The antioxidant capacity of the heterojunction Pdots is ~10 times higher than that of the single-component Pdots described previously. Under a total light dose of 360 J/cm2, the Lipo-Pdots nanoreactors effectively scavenged ⋅OH radicals and suppressed the expression of pro-inflammatory cytokines in skin tissues, thereby accelerating the healing of skin wounds in diabetic mice. This study provides a feasible solution for safe and effective treatment of diabetic foot ulcers.

Bacteriophage-cocktail hydrogel dressing to prevent multiple bacterial infections and heal diabetic ulcers in mice.

Bacteriophage (phage) has been reported to reduce the bacterial infection in delayed-healing wounds and, as a result, aiding in the healing of said wounds. In this study we investigated whether the presence of phage itself could help repair delayed-healing wounds in diabetic mice. Three strains of phage that target Salmonella enterica, Escherichia coli, and Pseudomonas aeruginosa were used. To prevent the phage liquid from running off the wound, the mixture of phage (phage-cocktail) was encapsulated in a porous hydrogel dressing made with three-dimensional printing. The phage-cocktail dressing was tested for its phage preservation and release efficacy, bacterial reduction, cytotoxicity with 3T3 fibroblast, and performance in repairing a sterile full-thickness skin wound in diabetic mice. The phage-cocktail dressing released 1.7%-5.7% of the phages embedded in 24 h, and reduced between 37%-79% of the surface bacteria compared with the blank dressing (p <.05). The phage-cocktail dressing exhibited no sign of cytotoxicity after 3 days (p <.05). In vivo studies showed that 14 days after incision, the full-thickness wound treated with a phage-cocktail dressing had a higher wound healing ratio compared with the blank dressing and control (p <.01). Histological analysis showed that the structure of the skin layers in the group treated with phage-cocktail dressing was restored in an orderly fashion. Compared with the blank dressing and control, the repaired tissue in the phage-cocktail dressing group had new capillary vessels and no sign of inflammation in its dermis, and its epidermis had a higher degree of re-epithelialization (p <.05). The slow-released phage has demonstrated positive effects in repairing diabetic skin wounds.

Injectable hydrogel harnessing foreskin mesenchymal stem cell-derived extracellular vesicles for treatment of chronic diabetic skin wounds

Chronic skin wounds are a serious complication of diabetes with a high incidence rate, which can lead to disability or even death. Previous studies have shown that mesenchymal stem cells derived extracellular vesicles (EVs) have beneficial effects on wound healing. However, the human foreskin mesenchymal stem cell (FSMSCs)-derived extracellular vesicle (FM-EV) has not yet been isolated and characterized. Furthermore, the limited supply and short lifespan of EVs also hinder their practical use. In this study, we developed an injectable dual-physical cross-linking hydrogel (PSiW) with self-healing, adhesive, and antibacterial properties, using polyvinylpyrrolidone and silicotungstic acid to load FM-EV. The EVs were evenly distributed in the hydrogel and continuously released. In vivo and vitro tests demonstrated that the synergistic effect of EVs and hydrogel could significantly promote the repair of diabetic wounds by regulating macrophage polarization, promoting angiogenesis, and improving the microenvironment. Overall, the obtained EVs-loaded hydrogels developed in this work exhibited promising applicability for the repair of chronic skin wounds in diabetes patients.

YAP/TAZ Drive Agrin–Matrix Metalloproteinase 12–Mediated Diabetic Skin Wound Healing

Macroscopic loss of extracellular matrix (ECM) can lead to chronic defects in skin wound healing, but supplementation of ECM holds promise for facilitating wound closure, particularly in diabetic wound healing. We recently showed that the ECM proteoglycan agrin accelerates cutaneous wound healing by improving mechanoperception of migrating keratinocytes and allowing them to respond to mechanical stresses via matrix metalloproteinase-12 (MMP12). RNA-sequencing analysis revealed that in addition to a disorganized ECM, agrin-depleted skin cells have impaired YAP/TAZ transcriptional outcomes, leading us to hypothesize that YAP/TAZ, as central mechanosensors, drive the functionality of agrin-MMP12 signaling during cutaneous wound repair. Herein, we demonstrate that agrin activates YAP/TAZ during migration of keratinocytes post-wounding in vitro and in vivo. Mechanistically, YAP/TAZ sustain agrin and MMP12 protein expression during migration post-wounding through positive feedback. YAP/TAZ silencing abolishes agrin-MMP12 mediated force-recognition and geometrical constraints. Importantly, soluble agrin (sAgrin) therapy accelerates wound closure in diabetic mouse models by engaging MMP12-YAP. Because patients with diabetic foot ulcers and impaired wound healing have reduced expression of agrin-MMP12 that correlates with YAP/TAZ inactivation, we propose that timely activation of YAP/TAZ by sAgrin therapy can accentuate mechanobiological microenvironments for efficient wound healing, under normal and diabetic conditions.

Hydrogen sulfide regulates macrophage polarization and necroptosis to accelerate diabetic skin wound healing

Hydrogen sulfide (H2S), recognized as the third gasotransmitter, plays a pivotal role in the pathophysiological processes of various diseases. Cystathionine γ-lyase (CSE) is the main enzyme for H2S production in the skin. However, effects and mechanisms of H2S in diabetic skin wound healing remain unclear. Our findings revealed a decrease in plasma H2S content in diabetic patients with skin wounds. CSE knockout (KO) diabetic mice resulted in delayed wound healing, reduced blood perfusion, and CD31 expression around the wounds. It also led to increased infiltration of inflammatory cells and M1-type macrophages, decreased collagen levels, α-smooth muscle actin (α-SMA), and proliferating cell nuclear antigen (PCNA) expression. Additionally, there were enhanced expressions of necroptosis related proteins, including receptor interacting protein kinase 1 (RIPK1), RIPK3 and mixed lineage kinase domain like protein (MLKL). In comparison, sodium hydrosulfide (NaHS), H2S donor, accelerated skin wound healing in leptin receptor deficiency (db/db) mice. This acceleration was accompanied by increased blood perfusion and CD31 expression, reduced infiltration of inflammatory cells and M1-type macrophages, elevated collagen levels, α-SMA, and PCNA expressions, and decreased necroptosis-related protein expressions together with nuclear factor-κB (NF-κB) p65 phosphorylation. In conclusion, H2S regulates macrophage polarization and necroptosis, contributing to the acceleration of diabetic skin wound healing. These findings offer a novel strategy for the treatment of diabetic skin wounds.

Multifunctional Hydrogel Enhances Inflammatory Control, Antimicrobial Activity, and Oxygenation to Promote Healing in Infectious Wounds.

Chronic infected wounds often fail to heal through normal repair mechanisms, and the persistent response of reactive oxygen species (ROS) and inflammation is a major contributing factor to the difficulty in their healing. In this context, we developed an ROS-responsive injectable hydrogel. This hydrogel is composed of ε-polylysine grafted (EPL) with caffeic acid (CA) and hyaluronic acid (HA) grafted with phenylboronic acid (PBA). Before the gelation process, a mixture CaO2@Cur-PDA (CCP) consisting of calcium peroxide (CaO2) coated with polydopamine (PDA) and curcumin (Cur) is embedded into the hydrogel. Under the conditions of chronic refractory wound environments, the hydrogel gradually dissociates. HA mimics the function of the extracellular matrix, while the released caffeic acid-grafted ε-polylysine (CE) effectively eliminates bacteria in the wound vicinity. Additionally, released CA also clears ROS and influences macrophage polarization. Subsequently, CCP further decomposes, releasing Cur, which promotes angiogenesis. This multifunctional hydrogel accelerates the repair of diabetic skin wounds infected with Staphylococcus aureus in vivo and holds promise as a candidate dressing for the healing of chronic refractory wounds.